As one of image forming apparatuses such as a printer, a facsimile, a copier, and a multifunction machine having printer, facsimile, and copier functions, an inkjet recording device is known. In the inkjet recording device, a recording head including a liquid drop discharging head for discharging a liquid drop (i.e., an ink drop) of recording liquid emits the liquid drop onto a conveyed recording sheet, so that the liquid drop is settled on the recording sheet to form (i.e., record or print) an image. The recording sheet is not restricted to paper, but also includes any medium on which the liquid drop can settle, such as a recorded medium, a recording medium, and a transfer material.
There are multiple types of the liquid drop discharging head, such as piezo, thermal, and electrostatic types. The piezo type uses an electromechanical sensing element such as a piezoelectric device. The thermal type uses an electric heat sensing element such as a heat generating resistance body provided in a discharging room to generate a bubble by boiling an ink film, so that pressure of the bubble discharges the ink drop. The electrostatic type uses a vibration board forming walls of the discharging room, so that the vibration board deformed by an electrostatic force discharges the ink drop.
In the image forming apparatus using the above inkjet recording method, however, ink on the recording sheet does not completely dry soon after an image is formed. To solve this problem, a straight output method is generally employed. According to the straight output method, the recording sheet is straight conveyed after an image is formed on the recording sheet, and then output face up.
A reverse output method is employed to correct curling generated in the recording sheet. According to the reverse output method, the recording sheet on which an image is formed is reversed, conveyed, and then output face down.
A sheet conveying apparatus for conveying the recording sheet is used in the image forming apparatus. In the sheet conveying apparatus, switching is performed among three conveyance paths, that is, a straight conveyance path, an upper conveyance path, and a lower conveyance path. The sheet conveying apparatus includes two path selectors and two drivers for independently operating the two path selectors. The two path selectors are rotatable about a single axis and positioned parallel to each other in such a manner as to sandwich a plane of sheet conveyance. One of the drivers drives one of the path selectors to close the straight conveyance path and to open the upper conveyance path. The other driver drives the other path selector to close the straight conveyance path and to open the lower conveyance path.